Objective: Cytomegalovirus (CMV) remains the leading opportunistic infection in the transplant population and is responsible for numerous direct and indirect consequences. Some clinical trials (Paya CV, et al. 2004; Ciancio G. et al 2004) have shown that prophylaxis with oral valganciclovir (VAL) is safe, effective and less costly when compared with IV ganciclovir (GAN) for the prevention of CMV infection in solid organ transplant (SOT) recipients. Our aim was to compare costs and medical resources of CMV infection prophylaxis in SOT recipients with oral VAL versus IV GAN in Brazil. Methods: Based on study of Paya CV, et al. 2004, we assumed the same efficacy for both oral VAL and IV GAN for the prevention of CMV infection in SOT recipients. Therefore, a cost-minimization analysis was developed to assess costs related to the prophylaxis of CMV with oral VAL (900mg/day) versus IV GAN (5mg/kg/day), under the payer's perspective in Brazil. Only direct medical costs (drugs, administration, physician fees and daily inpatient care) were considered in this study. A panel with specialists was conducted to reflect local practices. A 90-day timeframe was considered based on the prophylaxis period which begins until 10 days after the transplant is done; consequently a discount rate was not necessary. One-way sensitivity analyses were performed to assess the robustness of the outcomes. Results: Total costs were R$17,673 for VAL and R$45,625, a savings of 61% per patient. Cost-savings observed for VAL were due to lower costs related to inpatient care (VAL: R$0 vs. GAN: R$29,520) and lower administration costs (VAL: R$0 vs. GAN: R$7,564). One-way sensitivity analysis supported the robustness of the findings. Conclusion: Findings suggest oral valganciclovir as a cost-saving alternative for the prophylaxis of CMV infection in SOT recipients under the payer perspective in Brazil.